Knee twist sensing ski binding

ABSTRACT

A ski binding for preventing twist-type fractures of the lower leg has an elongated sensor element extending between the knee region of the skier and the ski boot and responsive to angular displacement of the knee relative to the foot so as to release a locking mechanism interconnecting the boot to the ski when excessive twist between the foot and the knee is detected. This sensor element can comprise a Bowden-type cable whose core projects more or less from the sheath as the leg is twisted. Alternately a nontwistable but otherwise flexible element extending from the knee to the latch in the boot is provided which operates the locking mechanism securing the boot to the ski.

United States Patent Courvoisier et al.

[451 Sept. 30, 1975 1 1 KNEE TWIST SENSING SKI BINDING [75] Inventors:Guy Courvoisier, Geneva; Pierre Comte, Troinex; Gerard Chevrolet,Damphreux, Bern, all of Switzerland [73] Assignee: F. Salomon & Fils,Annecy. France [22] Filed: Sept. 3, 1974 [21] Appl. No.: 502,728

[30] Foreign Application Priority Data Sept. 3. 1973 Switzerland12583/73 [52] US. Cl. 280/ll.35 D; 280/11.35 R [51] Int. Cl. A63C 9/08[58] Field ofSearch 280/11.35 R. 11.35 D, 280/] 1.35 M, 11.35 K, 11.35T, 11.36

156] References Cited UNITED STATES PATENTS 2,669.459 2/1954 Fleming280/11.35 R 2.803.467 8/1957 Von Opel 280/1 1.35 G

3.776.566 12/1973 Smolka 2230/1135 M Primary Examiner-David SchonbergAssistant Exzuniner-David M. Mitchell Attornqr, Agent, or Firm-Karl F.Ross; Herbert Dubno l 5 7 ABSTRACT A ski binding for preventingtwist-type fractures of the lower leg has an elongated sensor elementextending between the knee region of the skier and the ski boot andresponsive to angular displacement of the knee relative to the foot soas to release a locking mechanism interconnecting the boot to the skiwhen excessive twist between the foot and the knee is detected. Thissensor element can comprise a Bowden-type cable whose core projects moreor less from the sheath as the leg is twisted. Alternately anontwistable but otherwise flexible element extending from the knee tothe latch in the boot is provided which operates the locking mechanismsecuring the boot to the ski.

10 Claims, 16 Drawing Figures U.S. Patent Sept. 30,1975 Sheet 1 of 103,909,028-

U.S. Patent Sept. 30,1975 Sheet20f 10 3,909,028

US. Patent Sept. 30,1975 Sheet3 of 10 3,909,028

U.S. Patent Sept. 30,1975 Sheet4of 10 3,909,028

US Patent Sept. 30,1975 Sheet70f 10 3,909,028

FIG. Ila F/G. llb

US. Patent Sept. 30,1975 Sheet8ofl0 3,909,028

IOI

, IIIG III US. Patent Sept. 30,1975 Sheet9of 10 3,909,028

US. Patent set.30,1975 Sheet 10 of 10 3,909,028

I29 I30 I32 I35 I36 'IIIII KNEE TWIST SENSING SKI BINDING FIELD OF THEINVENTION The present invention relates to a ski binding. Moreparticularly, this invention concerns a safety ski binding of the typeadapted to release the ski when subjected to a predetermined force.

BACKGROUND OF THE INVENTION Safety ski bindings are known whichautomatically uncouple the skier from the ski when his leg or foot issubjected to a predetermined stress relative to the ski. Such a bindingis provided in order to prevent the relatively long lever armconstituted by the ski from breaking the users leg, a very commonincident prior to usage of such safety ski bindings.

A ski boot is usually secured to a ski in sucha manner that it can bedisengaged from the ski by forces acting in opposite directions. Thus ifa toe or heel of the skier pulls away from the ski with a forceexceeding a predetermined limit it is usual for such bindings to releasethe ski boot. Similarly it is desirable for the ski boot to be releasedif it is twisted about an axis generally perpendicular to the uppersurface of the ski so as to prevent so-called spiral fractures of theleg.

Although it has been found relatively simple by use of springs, smallhydraulic dashpots, and the like to provide means for releasing the heelor toe of the ski boot when raised from the surface of the ski, it hasbeen found extremely difficult to provide means which can hold the skiboot securely to the ski during strenuous skiing, but which will releasethe ski boot when it exerts a twist against the ski binding. Thisdifficulty is principally caused by the fact that the amount of twistwhich a particular skiers leg can withstand without fracture of any ofthe lower-leg bones or damage to the ankle or knee joint, is dependenton a great many factors such as the age of the skier, the strength ofhis joints, and the like. It has, however, been found generally to bethe case that the foot of a person cannot rotate relative to the knee ofa person about an axis passing upwardly through the lower leg by anangle of more than 25 without some degree of injury to the leg.

This fact' has been used in ski bindings wherein locking means securingthe ski boot to the ski can be operated by a mechanism actuated througha cable connected to the hips of the skier, thus he wears a sensor athis hips which is connected via a cable to his ski boots so that whenhis hips assume a predetermined angle relative to the ski boot, the skiboot will be released.

Such arrangements have the considerable disadvantage that the cablefollows the leg, thereby passing over the ankle and knee joints, so thatwhen the cable is deformed by bending at the ankles or knees theapparatus becomes almost totally ineffective. Thus it is possible forthe skier to bend at the knees and suddenly find that his ski boots havebeen. released from the binding, or similarly for him to be subjected toa sufficient strain to break his leg without his ski bindings releasing.This danger is particularly present when the cable is able to form aloop instead of transmitting a signal to the ski binding. Similarly whenthe cable is bent over on itself or otherwise kinked, as is the casewhen the skier is squatting on his skis, displacement of the body intwisting one leg will be read as a dangerous torsion for the other legand will not be responded to by the correct ski binding. As a rule suchcable-type sensors are almost totally ineffective when the upper andlower legs form an angle of approximately with one leg twisted relativeto the other leg. In this case it is possible for excessive strains tobe applied to one or both legs without the apparatus functioning.

OBJECTS OF THE INVENTION It is therefore an object of the presentinvention to provide an improved safety ski binding.

Another object is the provision of such an apparatus which will rapidlyrespond to a torsional stress applied to a skiers leg and cause thecorresponding ski boot to be released from the ski.

Yet another object is the provision of such a safety ski binding whichis inexpensive to manufacture and simple to adjust.

SUMMARY OF THE INVENTION These objects are attained according to thepresent invention in a ski binding comprising releasable locking meansfor securing a ski boot to a ski, sensor means including a knee-positiondetector adapted to be secured approximately to the knee of the skierand a footposition detector adapted to be secured approximately at thefoot or ankle of the skier and operating so as to generate an outputwhen the knee and foot regions are twisted relative to each other beyonda predetermined limit, and means interconnecting the sensor means andthe locking means for releasing the ski boot from the ski when thesensor produces the output indicating excessive twisting of the footrelative to the knee.

In accordance with the present invention the sensor means includes aflexible and elongated element having one end attached approximately atthe skiers knee and another end at the skiers foot or ankle to the skiboot. This latter lower end is connected to the locking mechanism whichsecures the boot to the ski so that when the foot and knee are twistedexcessively relative to each other the boot is released and is freedfrom the ski.

Thus according to the present invention the sensor comprises a pair oflike Bowden cables each having a sheath fixed to one side of the skiersknee and to the other side of the skiers foot so that these two sheathscross over each other, preferably in front of the skiers ankle. The corewires of these Bowden cables are secured at their upper ends to the kneeregion of the skier and are connected at their lower ends to the lockingmechanism of the ski boot. Thus-if the knee twists relative to the footor vice versa the one cable core or the other, depending on thedirection of twist, will move within its sheath and operate the lockingmechanism once a predetermined twist has been exceeded.

According to a further feature of this invention the elongated sensorelements have a pair of ends which are always at the same angularorientation relative to each other so that when one end is attached tothe knee the other end located at the foot will have an orientationexactly corresponding to the angular position of the knee relative tothe foot. Once again this lower end is connected to the lock-operatingmechanism so as to trip it and open the latch, thereby freeing the skiboot from the ski.

The arrangement in accordance with the present invention is built into aconventional ski boot and a legging which surrounds the lower leg, thatis the calf and ankle region of the skier. and encloses the knee of theskier.

In accordance with this invention the legging is provided with a pocketat the knee which is adapted to be filled with a hardeningsynthetic-resin foam so as to permit a custom fit of this knee portionto the individual skier. The boot is similarly provided with fillablepockets so as to allow to be custom-fitted to the skiers foot.

BRIEF DESCRIPTION OF THE DRAWING The above and other objects, features,and advantages will become more readily apparent from the following.reference being made to the accompanying drawing in which:

FIG. 1 is a schematic view illustrating the operation principles of theapparatus according to the present invention;

FIG. 2 is a perspective diagrammatic view illustrating the apparatus inaccordance with this invention;

FIG. 3 is a vertical section through the arrangement according to thepresent invention;

FIG. 4 is a perspective view illustrating features of the apparatusaccording to the present invention;

FIG. 5 is a vertical section through another arrangement according tothis invention;

FIG. 6 is a section taken along line VIVI of FIG. 5;

FIG. 7 is a view similar to FIG. 6 illustrating the apparatus in anotheroperative position;

FIG. 8 is a view similar to FIG. 6 illustrating a further arrangement inaccordance with the present invention;

FIG. 9 is a section taken along line lX-IX of FIG. 8;

FIG. 10 is a schematic view illustrating the operation principle of yetanother arrangement in accordance with this invention;

FIGS. 11a and 1112 are further schematic views illustrating theoperation of the apparatus illustrated schematically in FIG. 10;

FIG. 12 is a vertical section through an apparatus embodying theprinciples shown in FIG. 10;

FIG. 13 is a large-scale perspective view of a detail of the apparatusof FIG. 12; and

FIGS. 14 and 15 are views corresponding to FIGS. 12 and 13,respectively.

SPECIFIC DESCRIPTION FIG. 1 shows a cylinder s serving schematically toillustrate the lower leg of a skier. This cylinder s has an upper end bcorresponding to the knee region of the leg and a lower end ccorresponding to the foot and ankle region thereof. A limitedlyextensible and compressible tube g extends generally helically from oneend of this cylinder s to the other, being attached at a pointp at theend c and at a point q at the end b. A flexible but axially inextensiblecore wiref is received within the sleeve g and has an upper end attachedat a point q to the upper end b of the cylinder and a lower end whichextends from the tube g at p by distance equal to 1 Another tube g* isattached at the upper end b of the cylinder 5 at a point P, and has acore) extending below the lower end c of the cylinder 5. The cores g andg* are of opposite helical hand and have their ends spaced angularlyapart by an angle 7 equal to approximately 160, drawn to the centralaxis a of cylinder 3.

When the upper end b of the cylinder s is twisted in a direction Trelative to the lower end the corefwill retract within sleeve g by adistance equal to AI. Thus FIGS. 2, 3 and 4 show a ski boot 1 and alegging 2 which are interconnected in an accordion-pleated ankle region3 by a hinged member 4 on boot 1. The legging 2 is of flexible materialand is provided in the back with a slit 2a which is closable by means ofa slide fastener 7. The boot 1 is formed with a plurality of pocketsadapted to be filled with a synthetic-resin foam and the knee region ofthe legging 2 is adapted to be filled with a semi-rigid synthetic-resinbody 6 similarly so as to custom fit the apparatus according to thepresent invention both to the foot and the knee of the user.

A pair of like Bowden-type cables 8 and 9 each extend from therespective side of the knee insert 6 across the shin and to the back ofthe boot 1. The insert 6 is split in back at 6a so as to permit the shoeto be fitted around the calf and the knee of the skier. Each of thesleeves 8 and 9 is provided with a respective inextensible core wire 13connected via a bracket to the knee insert 6 and the core 13 isconnected to a riveted plate 14 carried on this insert. The lower endsof the tubes 8 and 9 are anchored at 11 on the boot 1.

Both of these cores 13 are connected to a common pin 14 slidable in aplate in boot I and pushed downwardly from this plate 15 by acompression spring 16. The lower end of the pin 14 is engaged in one arm17 of a two-arm lever L pivoted at 18 in boot 1 and having another arm20 formed with a nose 20a engageable in a notch 21 of an actuating rod22 of the locking mechanism for the boot 1. The boot 1 is formed with agenerally square recess 12 in which the upper end of the rod 14 and theends of the cores 13 are received so as to permit the operation thereof.

One end of the rod 22 is provided with a flexible cable 25 threadedthrough an eye 33 carried on the ski 32 and having an end received in alever 35 pivoted at 35* on the back of the boot :1 at 37. This lever 35allows the rod 22 to be pulled back so that the nose 20a can engage inthe notch 21. At the same time this cable 25 serves to secure the boot 1to the ski 32, so as to eliminate the conventional lanyard that preventsthe ski from escaping from the skier should he have a fall. A lever 19is provided on the lever arrangement L so as to permit manual actuationof this lever arrangement L and freeing of the rod 22.

The sole 24 of the boot 1 is formed with a parallelepipedal chamber 28terminating near the toe region 29 of the boot 1. The forward end 31 ofthe rod 22 carries a piston-like mechanism 30 received in a chamber 27ain a parallel epipedal body 27 in the chamber 28. The chamber 270 isprovided with a spring 31a to one side of the piston 30 and a spring 31to the other side thereof. The end 27b of the body 27 engages under thehead 34a of a locking element 34 carried on a shaft 36 extending betweentwo ears 37 on the ski 32. To the other side of this element 34 .thereis provided another block 36 so that this element 34 may be captured andsecurely held between these two elements 26, 27 so as to secure the boot1 to the ski 32. When the nose 20:: engages in notch 21 as shownin-FIGS. 2 and 3 the spring 31 forces the end 27b with considerableforce against the element 34. When, however, the nose a does not engagethe notch 21 it is possible for the block 27 to slide in the chamber 28toward toe 29 and therefore free the elements 34, allowing the boot 1 topull off the ski 32'. j

Thus it should be clear that in use. if the knee section 6 is twistedbeyond a predetermined extent to either side relative to the foot 1, oneof the core wires 13 will pull pin 14 up, thereby pivoting the leverarrangement L about its transverse axis 18 and freeing the rod 22. Thiswill have the immediate effect of unlatching the locking element 34 frombetween the end 27b of the element 27 and the nose 26a of the element26, thereby allowing the boot to slip off the ski 32. As the skier donsthe ski he threads the cable 35 through the eye 33 and connects the endsof the cable to the lever 35. Then he fits boot 1 over the lockingmember 34 and pulls up lever 35 so as to press the block 27 against thelatching element 34 and to engage the nose 20a in the latch 21. I

The arrangement shown in FIGS. 5-7 is similar in principle to that ofFIGS. 1-4, except that here a heel or toe clamp of conventional designis operated bya pair of Bowden-type cables 8* and 9* each having a core13* connected at the knee much as shown in FIGS. 1-4. The ski 41 isprovided with a plate carrying a rod 42 having a spherical head' 42awith a center 0 and formed with a semispherical recess 42b. A clampingbody 44 is formed with a pair of circular-section boards 44a and 44bwhich meet at a common point and have a semispherical base whose centerof curvature can correspond as shown in FIGS. 5 and 7'to the center 0 ofhead 42a.

This clamping body 44 is provided with a lower pedal jaw 45 and an upperlatchingjaw 45b so that the skier need merely step on the lower jaw 45aso as to pivot the entire body 44 down and lock his heel or toe in placewith the upper jaw 45b.

A piston 43 slidable in bore 440 has a head snugly receivable in therecess 42b and is urged by a spring 46 bearing against a cup 47 in bore44a. This piston 43 therefore defines a stable position of the body 44relative to the ski 41 so as to lock it in place in this position. Ofcourse as is known the force of spring 46 can be overcome by an upwardforce against the jaw 45b so as to release the skiers boot, should histoe or heel exert excessive upward force on this jaw 45b.

. The cup 47 is slidable piston-fashion in the bore 44a and is formedwith a ridge 470 which can engage a lever 48 pivoted at 49 in a recess50 formed in the body 44. This lever 48 has another arm formed with apair of bores 48a and 4811 which, as shown in IFG. 6, receive the cores13*. Balls 13a on the end of core 13* assure that displacement of thecore 13* in direction F, against the force of respective springs 51::and 51b will tip the lever, thereby pulling it into the position shownin FIG. 17. A loading lever 52 has a first arm 52a lying atop the body44 and a second arm 52b provided with an end 520 that can engage againstthe upper end of the cup 47 as shown in dot-dash lines in FIG. 5 so asto displace cup 47 down into the illustrated position. A tension spring54 engaged between a pivot 544 on the body 44 and the end 520 of thelever 52serves to pivot this lever about its axis 53 into the solid-lineposition of FIGS. 5 and 7.

Thus once the mechanism has been operated as shown in FIG. 7 to free thetoe of the ski boot. the skier can reset it simply by pulling up thelever 52.

' The arrangement of FIGS. 8 and 9 is similar in concept to that ofFIGS. 5-7. The ski 41 is again provided with a stem 42* having a head42*:1 with a center 0" .and formed with a recess 42*b. This head 42*a isrethrough which engages a lever 59 pivoted to one side of the piston at60 and having a boss 59:: engageable with one side of bore 580 so as todisplace the piston 58 on pivoting backwardly away from the ball head52%: as shown by dot-dash line. The two Bowdens 8* and 9* have theircores 13* passing through holes 59b and 59c in the lever 59,and providedat the opposite side thereof with lead balls 13*! so that displacementof these two coresl3* in the direction of arrows F will move the piston58 and the ballhead 52*a out of contact with each other and therebyallow the ski boot to be lifted away from the ski 41.

FIGS. 10, 11a and 1 lb illustrate another arrangement according to thepresent invention using the same cylinder s employed in the descriptionof FIG. 1. In this arrangernent. however an elongated sensor element dis provided which has an upper elemente, secured at the upper end b ofthe cylinder s and a lower end e secured at the lower end c of thecylinder s.

The element d is flexible. However its ends (1 and :1 cannot be twistedor deflected angularly relative to each other so that even when theelement (1 is bent the 40 angular orientation of, for instance, animaginary line on one end e bears the same relationship to a similarline on the other end e The upper end e. is rigidly fixed to the upperend b of cylinder s. End e howeve r, can rotate about its own axisrelative to cylinder s. In this manner, as will be described below, theorientation of the lower end e; to the lower end c of the cylinder s isthe same as the orientationof the upper end b of the cylinder to thelower end 0 thereof.

vAs shown in FIG. 110, if the upper end b is displaced through an angleof 7 so that the end e lies in a position e or is displaced through anangle of *7 so that it lies in a position corresponding to ef the lowerend e will be displaced so that an imaginary arrow 1', fixed radially onthis end will move into positions i,, or 11 respectively. Thesepositions at the lower end e correspond exactly to the positions of theupper end b.

When, as shown in FIG. 11b, the lower end c is twisted relative to theupper end through angle 'y or 'y is attached at its upper end near theknee of the skier by a plate 126 secured by rivets 127. Thiselement'comprises an upper part 125 formed with a polygonalsection core124 in which a lower element 116 telescopes. Both of these parts 125 and116 are flcxible but have ends which cannot be twisted readily angularlyrelative to one another so that a twist at the upper end of element 125is transmitted directly to the lower end of element 116.

In this arrangement an operating rod 100 is connected via a cable to alever 102 pivoted at 103 on a fulcrum 104 on the boot which serves tooperate via spring 113 a clamping element 114 similar to that describedin the abovd-mentioned embodiment.

The rod is formed with a notch 105 in which fits a tooth or nose 106 ofa lever 109 pivoted in the booth at 110 and urged down to the notch 105by means of a tension spring 111 secured in the boot at 1110 andreceived in a hole 112.

FIG. 13 shows in more detail the lower end of the element 116 shown tohave a radially projecting collar 116a adapted to prevent the element116 from being pushed up in the boot and from which extends a pair oflike arms 123 and 12311 carrying respective rollers 122 and 122a. Theserollers normally lie on respective planar surfaces 117 and 117a of asemicircular cam provided on the upper side of lever 109. When rotatedas shown by arrow F the roller can ride from surfaces 117 and 117a upover inclines and 1210 onto surfaces 118 and 119a. This presses the endof lever 109 down so as to lift the nose 106 from the notch 105.Similarly displacement in the opposite direction will displace therollers 122 and 122a up inclined surfaces 121 and 1204 onto surfaces 119and 118a, respectively. No matter which way the element 116 is twistedthis will effect a disengagement of nose 106 from notch 105. Thisreleases the rod 100 and allows the ski boot to pull free from the ski.

The arrangement of FIGS. 14 and 15 is very similar except that here thelever 135 of the unlatching arrangement 133 has a nose 131 which engagesin a notch of an actating rod 129. In addition this lever is formed atits rear end with an upper arm 137 having an eye 137a allowing the leverto have its front arm 132 lifted and the nose 131 disengaged from thenotch 130 manually.

The sensor element here has an upper part 149 secured to a plate 150held via rivets 151 to the knee region of the legging and is formed witha telescoping portion 148 and receives a lower section 144 having acollar 145 to prevent its upward or downward displacement in the boot.In addition the lever 133 has a cam arm 136 carrying a cam 138 normallyurged downwardly by a compression spring 128 and formed as shown in FIG.15 of semicircular shape.

As also shown in FIG. 15 the lower end 144 of the sensor rod has a hub144a carrying a pair of arms 146 and 146:: carrying respective rollers147 and 147a which normally rest on raised coplanar surfaces 139 and139a, respectively. Between these surfaces are'provided coplanar cammingsurfaces 140, 140:: and 141. Inclined regions 142, 143, 143a and 142ainterconnect the lower planar regions. Thus when the lower end 144 isrotated as shown by arrow F the rollers 147 and 147uare displaced fromthe regions 130 and 1390 and ride over the inclined region 142 and 1430onto the other regions 140 and 141 so as to allow the cam 138 lease-typeski binding, almost completely avoids the possibility of a leg fracturein skiing.

We claim: o

1. A safety ski binding comprising:

a ski boot adapted to receive the foot of a skier;

latch means for releasably securing said boot to a ski; a sensor meanshaving one portion carried at the knee region of said skier and anotherportion carried at the foot region of said skier adapted to senserelative movement of the two said portions; and

operating means connected between said sensor means and said latch meansfor operating same and releasing said boot from said ski when said kneeand foot regions are angularly offset to each other about an axispassing through said regions to an extent exceeding a predeterminedlimit.

2. The ski binding defined in claim 1 wherein said sensor meansincluding an elongated flexible element having one end constituting saidone portion and another end constituting said other portion andconnected to said operating means.

3. The ski binding defined in claim 2, further comprising means forsecuring said one end to said knee region and for securing said otherend to said foot region.

4. The ski binding defined in claim 2, furthercomprising a second suchsensor element having its one end secured to one side of said kneeregion and its other end passing over to the other side of said footregion, the first-mentioned sensor element having its one end secured tothe other side of said knee region and its other end passing over to theone side of said foot region.

5. The ski binding defined in claim 4 wherein said elements each includea tubular and flexible extensible sheath and an inextensible andflexible core received within said sheath, said cores being fixed atsaid one ends at said knee region and being secured at said other endsto said operating means. I

6. The ski binding defined in claim 5 wherein said operating meansincludes a pivotal lever assembly having one lever arm secured to saidcores.

7. The ski binding defined in claim 3 wherein said element is flexibleand said ends are angularly fixed relative to each other, said one endof said element being angularly fixed at said knee region and said otherend being angularly displaceable relative to said binding at said footregion, whereby the angular orientation of said other end relative tosaid binding at said foot region corresponds to the angular position ofsaid knee region relative to said foot region.

8. The ski binding defined in claim 7 wherein said operating meansincludes a pivotal lever assembly having one lever arm formed with a camengageable with said other end.

9. The ski binding defined in claim 8 wherein said other end carries aradially projecting arm and a roller on said arm engaging said cam.

10. The ski binding defined in claim 3 wherein said latch means includesa slidable body formed with a notch and said operating means includes apivotal lever assembly connected to said element and having a noseengageable in said notch for preventing sliding thereof. l= l

1. A safety ski binding comprising: a ski boot adapted to receive thefoot of a skier; latch means for releasably securing said boot to a ski;a sensor means having one portion carried at the knee region of saidskier and another portion carried at the foot region of said skieradapted to sense relative movement of the two said portions; andoperating means connected between said sensor means and said latch meansfor operating same and releasing said boot from said ski when said kneeand foot regions are angularly offset to each other about an axispassing through said regions to an extent exceeding a predeterminedlimit.
 2. The ski binding defined in claim 1 wherein said sensor meansincluding an elongated flexible element having one end constituting saidone portion and another end constituting said other portion andconnected to said operating means.
 3. The ski binding defined in claim2, further comprising means for securing said one end to said kneeregion and for securing said other end to said foot region.
 4. The sKibinding defined in claim 2, further comprising a second such sensorelement having its one end secured to one side of said knee region andits other end passing over to the other side of said foot region, thefirst-mentioned sensor element having its one end secured to the otherside of said knee region and its other end passing over to the one sideof said foot region.
 5. The ski binding defined in claim 4 wherein saidelements each include a tubular and flexible extensible sheath and aninextensible and flexible core received within said sheath, said coresbeing fixed at said one ends at said knee region and being secured atsaid other ends to said operating means.
 6. The ski binding defined inclaim 5 wherein said operating means includes a pivotal lever assemblyhaving one lever arm secured to said cores.
 7. The ski binding definedin claim 3 wherein said element is flexible and said ends are angularlyfixed relative to each other, said one end of said element beingangularly fixed at said knee region and said other end being angularlydisplaceable relative to said binding at said foot region, whereby theangular orientation of said other end relative to said binding at saidfoot region corresponds to the angular position of said knee regionrelative to said foot region.
 8. The ski binding defined in claim 7wherein said operating means includes a pivotal lever assembly havingone lever arm formed with a cam engageable with said other end.
 9. Theski binding defined in claim 8 wherein said other end carries a radiallyprojecting arm and a roller on said arm engaging said cam.
 10. The skibinding defined in claim 3 wherein said latch means includes a slidablebody formed with a notch and said operating means includes a pivotallever assembly connected to said element and having a nose engageable insaid notch for preventing sliding thereof.